The determination of hardness distribution below the surface of plastics with the aid of Vickers hardness tests involving several load levels

A description is given of a testing and evaluation procedure which makes it possible to calculate the hardness distribution under the surface on the basis of data obtained with the aid of microhardness measurements at the specimen surface. Vickers hardness tests involving different indentation depths are conducted. An experimentally determined 'weight function' is used in the evaluation of the test data. The application of the described procedure is demonstrated with the aid of two examples, including a study of thin specimens made of plastics and the determination of the hardness gradient at the surface of a quenched polyethylene sample.